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🔗 Physics 🔗 Physics/Acoustics

Thermoacoustic engines (sometimes called "TA engines") are thermoacoustic devices which use high-amplitude sound waves to pump heat from one place to another (this requires work, which is provided by the loudspeaker) or use a heat difference to produce work in the form of sound waves (these waves can then be converted into electrical current the same way as a microphone does).

These devices can be designed to use either standing wave or travelling wave.

Compared to vapor refrigerators, thermoacoustic refrigerators have no coolant and few moving parts (only the loudspeaker), therefore require no dynamic sealing or lubrication.

🔗 Germany 🔗 Time 🔗 Radio Stations

DCF77 is a German longwave time signal and standard-frequency radio station. It started service as a standard-frequency station on 1 January 1959. In June 1973 date and time information was added. Its primary and backup transmitter are located at 50°0′56″N 9°00′39″E in Mainflingen, about 25 km south-east of Frankfurt am Main, Germany. The transmitter generates a nominal power of 50 kW, of which about 30 to 35 kW can be radiated via a T-antenna.

DCF77 is controlled by the Physikalisch-Technische Bundesanstalt (PTB), Germany's national physics laboratory and transmits in continuous operation (24 hours). It is operated by Media Broadcast GmbH (previously a subsidiary of Deutsche Telekom AG), on behalf of the PTB. With Media Broadcast GmbH, a temporal transmission availability of at least 99.7% per year or under 26.28 hours of annual downtime has been agreed upon. Most service interruptions are short-term disconnections of under two minutes. Longer lasting transmission service interruptions are generally caused by strong winds, freezing rain or snow-induced T-antenna movement. This manifests itself in electrical detuning of the antenna resonance circuit and hence a measurable phase modulation of the received signal. When the maladjustment is too large, the transmitter is taken out of service temporarily. In the year 2002, almost 99.95% availability, or just over 4.38 hours of downtime, was realized. The timestamp sent is either in Coordinated Universal Time (UTC)+1 or UTC+2 depending on daylight saving time.

The highly accurate 77.5 kHz (approximately 3868.3 m wavelength) carrier signal is generated from local atomic clocks that are linked with the German master clocks at the PTB in Braunschweig. The DCF77 time signal is used for the dissemination of the German national legal time to the public.

Radio clocks and watches have been very popular in Europe since the late 1980s and, in mainland Europe, most of them use the DCF77 signal to set their time automatically. Further industrial time-keeping systems at railway stations, in the field of telecommunication and information technology, and at radio and TV stations are radio-controlled by DCF77 as well as tariff change-over clocks of energy supply companies and clocks in traffic-light facilities.

🔗 Disaster management 🔗 Death 🔗 Kansas City 🔗 Missouri

On July 17, 1981, two walkways collapsed at the Hyatt Regency Kansas City hotel in Kansas City, Missouri, one directly above the other. They crashed onto a tea dance being held in the hotel's lobby, killing 114 and injuring 216. As a product of a corporate culture of profound neglect, the disaster contributed many lessons to the study of engineering ethics and errors, and to emergency management. The event remains the deadliest non‑deliberate structural failure in American history, and it was the deadliest structural collapse in the U.S. until the collapse of the World Trade Center towers 20 years later.

🔗 United States 🔗 Film 🔗 Library of Congress 🔗 Film/American cinema 🔗 Film/Silent films 🔗 Film/Documentary films 🔗 United States/Film - American cinema

A Trip Down Market Street is a 13-minute actuality film recorded by placing a movie camera on the front of a cable car as it traveled down San Francisco’s Market Street. The film shows many details of daily life in a major early 20th century American city, including the transportation, fashions and architecture of the era. The film begins at 8th Street and continues eastward to the cable car turntable, at The Embarcadero, in front of the Ferry Building. Landmarks passed in the latter part of the first half include the Call Building (then San Francisco's tallest) and the Palace Hotel (both on the right; Lotta's Fountain is on the left between the two but is in the shade). The film was produced by the four Miles brothers: Harry, Herbert, Earle and Joe. It is notable for capturing San Francisco four days before the 1906 San Francisco earthquake, which started on the morning of Wednesday, April 18, 1906.

The Miles brothers had been producing films in New York including films shot in San Francisco. In September 1905 they shot the fight between Oscar "Battling" Nelson and Jimmy Britt in Colma, California, just south of San Francisco city limits. The Miles brothers established a studio at 1139 Market Street in San Francisco in early 1906. They shot a railroad descent down Mount Tamalpais as well as the Market Street film. On April 17, Harry and Joe Miles boarded a train for New York, taking the two films with them, but they heard about the earthquake and sent the films to New York while they boarded another train headed back to San Francisco. The Turk Street house of Earle Miles survived the earthquake and subsequent catastrophic fire but the studio did not. The Miles brothers based their business out of Earle's home, and shot more film of post-earthquake scenes; some of this footage, including that of a second trip down a now devastated Market Street, reemerged in 2016. It is likely that the Market Street film survives today because it was sent away before the fire.

Several 35mm prints exist with slight changes in footage. Copies are held at the Library of Congress and the Prelinger Archives. A digital version is viewable online at Internet Archive, YouTube and Wikimedia Commons. In 2010, the film was selected for preservation in the National Film Registry by the Library of Congress.

🔗 Computing 🔗 Computing/Computer Security

An .XIP file is a XAR archive which can be digitally signed for integrity. The .XIP file format was introduced in OS X 10.9, along with Apple's release of Swift. .XIP allows for a digital signature to be applied and verified on the receiving system before the archive is expanded. When a XIP file is opened (by double-clicking), Archive Utility will automatically expand it (but only if the digital signature is intact).

Apple has reserved the right to use the .XIP file format exclusively, removing it from public use since release. Starting with macOS Sierra, only .XIP archives signed by Apple will be expanded. Developers who had been using .XIP archives were required to move to using signed installer packages or disk images.

🔗 Insects

The emerald cockroach wasp or jewel wasp (Ampulex compressa) is a solitary wasp of the family Ampulicidae. It is known for its unusual reproductive behavior, which involves stinging a cockroach and using it as a host for its larvae. It thus belongs to the entomophagous parasites.

🔗 Philosophy 🔗 Philosophy/Ethics

The hedonic treadmill, also known as hedonic adaptation, is the observed tendency of humans to quickly return to a relatively stable level of happiness despite major positive or negative events or life changes. According to this theory, as a person makes more money, expectations and desires rise in tandem, which results in no permanent gain in happiness. Brickman and Donald T. Campbell coined the term in their essay "Hedonic Relativism and Planning the Good Society" (1971). The concept dates back centuries, to such writers as St. Augustine, cited in Robert Burton's 1621 Anatomy of Melancholy: "A true saying it is, Desire hath no rest, is infinite in itself, endless, and as one calls it, a perpetual rack, or horse-mill."

The hedonic (or happiness) set point has gained interest throughout the field of positive psychology where it has been developed and revised further. Given that hedonic adaptation generally demonstrates that a person's long-term happiness is not significantly affected by otherwise impacting events, positive psychology has concerned itself with the discovery of things that can lead to lasting changes in happiness levels.

🔗 Psychology 🔗 Gender Studies

Wife acceptance factor, wife approval factor, or wife appeal factor (WAF) is an assessment of design elements that either increase or diminish the likelihood a wife will approve the purchase of expensive consumer electronics products such as high-fidelity loudspeakers, home theater systems and personal computers. Stylish, compact forms and appealing colors are commonly considered to have a high WAF. The term is a tongue-in-cheek play on electronics jargon such as "form factor" and "power factor" and derives from the idea that men are predisposed to appreciate gadgetry and performance criteria whereas women must be wooed by visual and aesthetic factors.

🔗 Human rights 🔗 Internet 🔗 Religion 🔗 Comedy 🔗 Freedom of speech 🔗 Islam 🔗 Journalism 🔗 Animation 🔗 Comics 🔗 South Park

Everybody Draw Mohammed Day (or Draw Mohammed Day) was a 2010 event in support of artists threatened with violence for drawing representations of the Islamic prophet Muhammad. It stemmed from a protest against censorship of the American television show South Park episode "201", led by the show's distributor Comedy Central, in response to death threats that had been made against some of those responsible for two segments broadcast in April 2010. A drawing representing Mohammed was posted on the Internet on April 20, 2010, with a message suggesting that "everybody" create a drawing depicting Mohammad on May 20 in support of free speech.

U.S. cartoonist Molly Norris of Seattle, Washington created the artwork in reaction to Internet death threats that had been made against animators Trey Parker and Matt Stone for depicting Muhammad in an episode of South Park. Postings on RevolutionMuslim.com (under the pen name Abu Talha al-Amrikee; later identified as Zachary Adam Chesser) had said that Parker and Stone could wind up like Theo van Gogh, a Dutch filmmaker who was stabbed and shot to death.

Norris claimed that, if people draw pictures of Muhammad, radical Islamist terrorists would not be able to murder them all, and threats to do so would become unrealistic. Within a week, Norris' idea became popular on Facebook, was supported by numerous bloggers, and generated coverage on the blog websites of major U.S. newspapers. As the publicity mounted, Norris and the man who created the first Facebook page promoting the May 20 event disassociated themselves from it. Nonetheless, planning for the protest continued with others "taking up the cause". Facebook had an "Everybody Draw Mohammed Day" page, which grew to over 100,000 participants (101,870 members by May 20). A protest page on Facebook against the initiative named "Against ‘Everybody Draw Mohammed Day'" attracted slightly more supporters (106,000 by May 20). Subsequently, Facebook was temporarily blocked by Pakistan; the ban was lifted after Facebook agreed to block the page for users in India and Pakistan.

In the media, Everybody Draw Mohammed Day attracted support from commentators who felt that the campaign represented important issues of freedom of speech, and the need to stand up for this freedom.

🔗 Food and drink 🔗 Iceland

Although Iceland is reliant upon fishing, tourism and aluminium production as the mainstays of its economy, the production of vegetables and fruit in greenhouses is a growing sector. Until the 1960s this included commercial production of bananas.

In 1941, the first bananas in Iceland were produced. They have been produced since that time, about 100 clusters a year each about 5–20 kg (11–44 lb), but are not currently sold. In the wake of World War II, the combination of inexpensive geothermal power (which had recently become available) and high prices for imported fruit led to the construction of a number of greenhouses where bananas were produced commercially from 1945 to as late as 1958 or 1959. In 1960, the government removed import duties on fruit. Domestically grown bananas were no longer able to compete with imported ones and soon disappeared from the market. Icelandic banana production was much slower due to low levels of sunlight; Icelandic bananas took two years to mature, while it only takes a few months near the equator.

The urban myth that Iceland is Europe’s largest producer or exporter of bananas has been propagated in various books and other media. It was mentioned, in an episode of the BBC quiz programme QI, and on a forum connected with the show. According to FAO statistics, the largest European producer of bananas is France (in Martinique and Guadeloupe), followed by Spain (primarily in the Canary Islands). Other banana-producing countries in Europe include Portugal (on Madeira), Greece, and Italy.

Although a small number of banana plants still exist in greenhouses and produce fruit every year, Iceland imports nearly all of the bananas consumed in the country, with imports now amounting to over 18 kg (40 lb) per capita per annum. The Agricultural University of Iceland maintains the last such farm with 600-700 banana plants in its tropical greenhouse, which were received as donations from producers when they shut down (then the Horticultural College). Bananas grown there are consumed by the students and staff and are not sold.